EXPERIMENTAL AND THERAPEUTIC MEDICINE 5: 942-946, 2013
942
Expression of a tumor-associated gene, LASS2, in the human bladder carcinoma cell lines BIU-87, T24, EJ and EJ-M3 QINGHUA ZHAO1*, HAIFENG WANG2*, MINGYING YANG2, DELIN YANG2, YIGANG ZUO2 and JIANSONG WANG2 Departments of 1Gynaecology and 2Urology, The Second Affiliated Hospital of Kunming Medical University, Yunnan Institute of Urology, Kunming 650101, P.R. China Received November 20, 2012; Accepted January 2, 2013 DOI: 10.3892/etm.2013.892 Abstract. Homo sapiens longevity assurance homolog 2 of yeast LAG1 (LASS2), a metastasis suppressor gene of human cancer, is the most abundantly expressed member of the ceramide synthase gene family. Expression of LASS2 has been reported in carcinomas of the prostate, liver and breast. However, there has been no report on the expression of LASS2 in human bladder cancer cell lines. In order to investigate the expression and potential role of this new tumor metastasis supressor gene in human bladder cancer, we compared the proliferation, metastasis and invasion among the BIU-87, T24, EJ and EJ-M3 human bladder cancer cell lines. The mRNA expression levels of the LASS2 gene were examined using real-time quantitative PCR (qPCR). The expression levels of LASS1 and LASS3 mRNA were used as references. The protein expression level of the LASS2 gene was detected using western blotting. The most aggressive of these four human cancer cell lines was observed to be EJ-M3. The expression of LASS2 mRNA was significantly correlated with diverse proliferation, metastasis and invasion. The expression levels of LASS1 and LASS3 mRNA were not correlated with these parameters. At the protein level, we observed that the more aggressive the cancer cell line, the lower the LASS2 protein expression level. Therefore, LASS2 expression may be correlated with the development and progression of human bladder cancer and may be a prognostic indicator for this cancer. Introduction Bladder cancer is one category of common genitourinary cancers and recurrence with metastasis is the main reason for
Correspondence to: Professor Jiansong Wang, Department of
Urology, The Second Affiliated Hospital of Kunming Medical University, 374 Dianmian Avenue, Kunming, Yunnan 650101, P.R. China E-mail:
[email protected] *
Contributed equally
Key words: bladder cancer, Homo sapiens longevity assurance homolog 2 of yeast LAG1, expression, biological characteristics
treatment failure (1). Metastases are the end result of tumor progression and the most common cause of mortality in cancer patients. The process of metastasis is multistep and interruption of this process at any individual step may arrest the metastatic cascade (2). Therefore, it is important to investigate the biological mechanisms contributing to the development and metastatic movement of bladder cancer. Tumor metastasis suppressor genes are a relatively new class of genes. These genes, which include NM23 (3-7), KISS‑1 (8‑11) and RhoGDI2 (12-14), reduce the metastatic ability of cancer cells at orthotopic sites,. However, the mechanism of action and role in human cancer remains unknown for the majority of these genes. The LASS (longevity assurance homolog) family members are highly conserved from yeasts to mammals. Homo sapiens longevity assurance homolog 2 of yeast LAG1 (LASS2), also known as tumor metastasis suppressor gene 1 (TMSG1, GenBank accession number AF189062), is a gene isolated from a human liver cDNA library by the laboratory of Shanghai Medical College, Fudan University (Shanghai, China), and it is a human homolog of the yeast (Saccharomyces cerevisiae) longevity assurance gene, LAG1. LASS2 has been observed to correlate with the degree of invasion and recurrence in carcinomas of the prostate (15,16), liver (17) and breast (18). However, there has been no report on the expression of LASS2 in human bladder cancer cell lines. In our previous study, we demonstrated that LASS2‑negative bladder cancer was associated with poor clinical prognosis. The expression of LASS2 mRNA was significantly correlated with clinical stage (P
